Table 1.

Tuberculosis Diagnostics: Approved Modalities and Those in Advanced Stages of Development

Modality	Example	Strength	Weakness	Sensitivity	Affordability	Simplicity	Principal Setting	Speed of Detection
Smear microscopy	Ziehl-Neelsen, Auramine	Minimal equipment required; low cost	Poor sensitivity, especially for extrapulmonary tuberculosis, children, and HIV coinfection; operator-dependent; no DST	Low	Inexpensive	Simple	Local labs	Rapid
Traditional solid culture on egg-based media	Ogawa, Lowenstein-Jensen	Low cost; simple; robust; can provide DST	Some biosafety concerns; DST usually delayed after detection; poorly standardized; moderate sensitivity	Moderate	Moderate	Simple	Regional labs	Slow
Modern culture on synthetic media	BACTEC MGIT, thin-layer agar	Sensitive; provides DST; well validated for extrapulmonary tuberculosis	Biosafety concerns; training and equipment requirements; cross-contamination and inability to detect polyclonal infection (liquid); DST usually delayed after detection; requires international cold chain supplies	High	Moderate/Expensive	Moderate	Regional labs	Intermediate
MODS	In-house protocol; Hardy kit	Simultaneous DST; sensitive; rapid for culture	Biosafety concerns; training and equipment requirements; requires international cold chain supplies	High	Moderate/Expensive	Moderate	Regional labs	Intermediate
NAAT	Amplicor, Gen-Probe, LAMP, GeneXpert	Simultaneous DST; most tests are simple; biosafety	Genotypic DST has uncertain clinical implications; moderate sensitivity	Moderate	Moderate/Expensive	Moderate/Simple	Local/Regional labs	Rapid
Line probe	INNO-LiPARif, MTBDR	Provides rapid DST for patients known to have tuberculosis	Expensive; complex; principally used for DST, not tuberculosis diagnosis; genotypic DST has uncertain clinical implications; requires international cold chain supplies	Low	Expensive	Complex	Regional labs	Rapid
LAM	TB ELISA	Nonsputum based	Low sensitivity in HIV-uninfected patients	Low	Undefined	Moderate	Regional labs?	Rapid

Abbreviations: DST, drug-susceptibility testing; HIV, human immunodeficiency virus; LAM, lipoarabinomannan; LAMP, loop-mediated isothermal amplification; MODS, microscopic-observation drug susceptibility; NAAT, nucleic acid amplification tests.